You can have a look at maximum penalties for possession here.
You're looking at a fine of $500 - $1000 (for a first offender, it's going to be on the lower end of the scale) and a mandatory 6 month suspension of your license if you're convicted.
You're likely eligible for a conditional discharge - consult with an attorney in your area about requirements. Conditional discharge will result in no record and no license suspension.
As for the hotel, you might be able to fight them, but it would cost you more in attorney and court fees to do so.
And:
I doubt this muchly. Unsmoked mary jane smells, but a bit more than a gram is not going to stink up a hotel room unless you rubbed it all over the walls. You'd have a really, really hard time arguing this in court.The smell was from the weed that was with me.

